Malicious RTF — malware analysis report

Static analysis result for SHA-256 9354bdc47d50f40a…

MALICIOUS

RTF

7.2 KB First seen: 2019-09-30
MD5: 6c204b8af8749417dffea41b6017b2a6 SHA-1: 46ac62890f1e6dd5ec8cd92e3d87e5bc02d573de SHA-256: 9354bdc47d50f40a234a53ebb2cd279281bb43cbd1d06968887cffa9259d5fb5
240 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The RTF file contains embedded OLE object data, specifically triggering critical heuristics for CVE-2017-11882 related to an Equation Editor font record overflow. This indicates the file is designed to exploit this vulnerability for client execution. The presence of ".objupdate" further suggests an attempt to force OLE activation. Given the nature of the exploit, it is highly likely to be delivered via spearphishing.

Heuristics 5

  • Equation Editor CLSID critical CVE likely RTF_EQUATION_EDITOR
    Equation Editor OLE CLSID found inside an OLE object — exploited by CVE-2017-11882 / CVE-2018-0802 / CVE-2018-0798
  • CVE-2017-11882 — Equation Editor FONT record overflow critical CVE likely CVE_2017_11882
    Equation Editor MTEF contains an overlong FONT typeface field, the vulnerable copy primitive for CVE-2017-11882. This is stronger evidence than the Equation Editor CLSID alone because it identifies the malformed record that drives code execution in EQNEDT32.EXE.
  • ClamAV: Doc.Exploit.CVE_2017_11882-6934206-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Exploit.CVE_2017_11882-6934206-0
  • \objupdate forces OLE activation high RTF_OBJUPDATE
    RTF contains \objupdate — forces automatic OLE object instantiation when the document is opened, bypassing user interaction. Almost exclusively seen in Equation Editor exploit documents.
  • OLE object data medium RTF_OBJDATA
    RTF contains 1 \objdata section(s) — embedded OLE objects

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off0000003c.bin rtf-objdata-decoded RTF \objdata at offset 0x3C 3639 bytes
SHA-256: a7a79a0523405fadd2c8b66ceaa57f89f94ee5ca15f91405d4b11373eaf6683a